1. Technical Field
The present invention generally relates to simulation devices for simulating combat-type scenarios to missile seekers and, more particularly, to a simulation device for simulating a far-away missile target against a sky-temperature background or a space-temperature background with a hot, point-like target against a given temperature background.
2. Discussion
As with other military devices, missile seeker systems and missile seeker operators require periodic testing and training. To accomplish this in the most economically feasible manner, simulation devices have been devised to replicate a scene typically encountered by the missile seeker and operator in real life circumstances. Commonly, the scene to be replicated includes a hot target, (e.g., a missile), against a given temperature background, (e.g., sky or space).
To present a realistic but simulated scene to the missile seeker, the simulator must present a hot, point-like target against a spatially uniform and temporally stable background. Conventional simulators typically utilize one of two types of background sources for this purpose, emissive-type or reflective-type. An emissive-type background source sits at room temperature and radiometrically emits a temperature that is exactly the same temperature as its ambient surroundings. As the temperature of the surroundings change, the temperature of the background source also changes. At times, this may cause an unwanted artifact when testing sensitive missile seeker detectors. A reflective type background source overcomes this problem by radiometrically reflecting the temperature of an external, controllable source. The controlled source is typically near ambient temperature, but does not fluctuate over time. The controllable source is commonly referred to as a plate or extended blackbody.
Prior art simulators employing emissive-type background sources replicate only cold, space-like backgrounds without a hot point-like target source. Adding a hot point source against the cold background is advantageous for simulating more realistic scenarios for the missile seeker. Prior art attempts to add a hot point source to the cold background have resulted in stray light noise within the simulation. Furthermore, illuminating a pinhole target etched on the surface of an emissive-type cold blackbody typically results in localized heating of the area presented as the cold background and distortion of the target.
Prior art simulators employing reflective-type backgrounds to replicate warmer, sky-like backgrounds, fail to supply a featureless and specular (i.e., "clean") background. Due to the poor surface quality of the polished metal substrates used to date, these backgrounds have poor uniformity and exhibit stray light noise. High spatial uniformity is necessary for critical missile seeker performance tests such as target-tracking and high temporal stability is important for critical optical characterization tests.
Therefore, it would be desirable to provide a missile seeker simulator for providing a hot, point-like target against an emissive-type background without localized heating of the background and without stray light noise. It would also be desirable for providing a missile seeker simulator for providing a hot, point-like target against a spatially uniform and temporally stable reflective-type background. It would also be desirable to provide a modular missile seeker simulator for use in field testing at remote locations.